1. Technical Field
This invention generally relates to an orthopedic instrument used to distract a joint, and more particularly, to a segmented joint distractor which allows for access into a distracted joint.
2. Discussion
Joint arthroscopy is a relatively young treatment modality for treating painful joints. Its primary function is to diagnose joint pathology. Additionally, debridement, joint flushing and smoothing of the joint surfaces has led to reduced pain and a return to more normal activities.
An important step in arthroscopy is to assure that not only are the bones of the joint properly aligned, but also that both joint surfaces are accessible. Failure of both joint surfaces being accessible can lead to significant trauma to the surrounding joint soft tissue, which leads to significant recovery time.
The joint surfaces are spanned by muscles, ligaments or other soft tissue. For example, in the knee joint, the collateral ligaments are both equally tight in the joint. This tension in the collateral ligaments prevents sideways toggle of the appendage. The ACL and PCL limit the amount of anterior and posterior motion in the knee joint. These ligaments limit the amount the joint can be separated to create access to the joint surfaces.
The knee is a superficial joint because there is little soft tissue between the skin and the joint as compared to the hip. Access is achieved by a combination of flexion and extension to give the clinician direct view of the various anatomic structures. At times, hand distraction and rotation can be used to increase exposure.
While the current invention has more application in total joint surgery where ligament balancing is key, it has uses in other surgical procedures. In another example, gaining access to the bearing surfaces of a hip joint with minimal tissue disruption is often complex and relatively ineffective. Current methods, for example, to perform hip arthroscopy utilize elongated arthroscopy instruments to obtain access to the joint which lies under many thick layers of muscle and soft tissue. Distraction normally is applied to the leg to create approximately 5 to 7 millimeters of joint displacement. Access to limited portions of the intra-articular area can then be achieved.
This distraction of the joint applies force to the patient""s foot and a counterforce to the patient""s groin area. This mode of distraction is only marginally effective. Possible side effects to this surgery include numbness, nerve damage, and impotence. Additionally, the immobilized leg is not free to be manipulated to allow visualization of the articular cartilage areas.
Other apparatus attempt to separate various inner body regions by use of a fluid operated regulator. Typically, a balloon is positioned at the desired location within the body for developing an atomic space at the desired location. The apparatus typically includes a tunneling member and an inflatable balloon. The tunneling member has a substantially rigid tubular shaft with proximal and distal ends and a passage extending through the ends, and having an opening in the proximal end to receive an inflatable balloon. The balloon generally comprises a substantially flexible, and preferably non-elastic, material having an inflatable space therein, defining a predetermined shape capable of assuming collapsed and inflated conditions.
Inherent with these types of balloon distractors, is that the surface which needs to be observed or worked on is often covered by the balloon material. Inherent in arthroscopic surgeries is a need to access Joint surfaces. As such, what is needed then is a joint distractor that does not suffer from the above-mentioned disadvantages. This, in turn, will provide a substantially conforming joint distractor between the articular cartilage areas, allow for visualization of the articular cartilage areas, and allow for debridement, joint flushing, and smoothing of the joint surfaces.
In accordance with the teachings of the present invention, a segmented joint distractor for use in the surgical distraction of a joint is disclosed. The segmented joint distractor provides the necessary force and contact surface on the articular cartilage areas to separate the joint while also providing sufficient access to the joint to perform arthroscopic surgical procedures.
In one preferred embodiment, the segmented joint distractor includes a series of fluidly filled spheroids. Disposed between the spheroids is a generally non-expandable pipe region, which allows access to the intra-ariticular area and fluidly couples the spheroids.
In yet another preferred embodiment, a joint distractor having a sequence of circular disks that start flat and increase in thickness is disclosed. Further, a method of distracting the joint by pulling the sequence through a joint to steadily increase the thickness and, hence, the amount of distraction is disclosed.
In yet another preferred embodiment, a joint distractor for separating the intra-articular areas includes a string of varying diameter beads. The string of beads has a series of increasing diameter spheroids strung onto a cord member. The method of distracting a joint is disclosed. The beaded cord is inserted into the joint and pulled through, steadily separating the articular cartilage areas.
Use of the present invention provides a segmented joint distractor with spherical members. The joint distractor provides a substantially full contact surface area on each of the generally spherical members. Between the spherical members, access can be gained to the articular cartilage areas of the joint. As a result, the aforementioned disadvantages associated with the currently available joint distractors have been substantially reduced or eliminated.